Electrolytic device



Nov. 4, 1947.

J. a. BRENNAN 2,429,987

ELECTROLYTIC DEVICE Original Filed July 13, 1938 N INVENTOR. JOSEPH B. BEEN/VAN Patented Nov. 4, 1947 UNITED STATES PATENT orncs ELECTROLYTIC DEVICE Joseph B. Brennan, Euclid, Ohio Original application July 13, 1938, Serial No.

218,910. Divided and this application December 29, 1941, Serial No. 424,763

3 Claims. (Cl. 175-315) now Patent No. 2,280,789, issued April 28, 1942. 1

One of the objects of my invention is to provlde efficient, durable and economical electrolytic condensers, lightning arresters, rectiflers, and the like, which can be manufactured with the use of a minimum amount of metal. Another object is to provide devices of this character which will have high capaciies in proportion to their size. Another object is to provide such devices which can be made largely of abundant and inexpensive materials.

Further objects and advantages of my invention will become apparent from the following description of preferred forms thereof, reference being made to the accompanying drawings in which Fig. l is a plan view of a preferred form of my invention as adapted for electrolytic condensers of the dry or paste type, part of the assembly being broken away for convenience of illustration; Fig. 2 is a transverse section taken along the line 2-2 of Fig. 1; Fig. 3 is a section taken along the line 8-4 of Fig. 1; Fig, 4 is a vertical section illustrating a condenser of the wet type embodying my invention; and Fig. 5 is a section as indicated by the line H of Fig. 4.

Briefly, my invention as applied, for example, to an electrolytic'condenser contemplates a construction in which the electrolyte is retain d within a member having an inner coating of aluminum or other suitable film forming metal. this being provided with a dielectric film if it is intended to constitute the anode of the condenser. Preferably the coating is produced by spraying molten metal on the surface of the member as described, for example, in my Patent No, 2,104,018 issued January 4, 1938. The

member is preferably made of an inexpensive material, with an inner surface composed of an insulating material which is resistant to the action of the electrolyte'such as glass, porcelain, various synthetic resins, and the like, which forms a base or support for the spray deposited coating. In order to increase the area of the member, the inner surface thereof is preferably provided with flutes or corrugations. To further increase the capacity of the condenser, flexible electrode members conforming at least in part in contour to the electrolyte retaining member, and provided with spray deposited active surfaces are also employed. The other electrode may be of similar construction or. in some instances, may constitute simply a conductive rod suspended within the electrolyte, depending upon the service for which the condenser is intended.

Referring now to Figs. 1 to 3 of the drawings in which I have illustrated a paste type electrolytic condenser embodying a preferred form of my invention, the condenser may comprise two similar forms l0 and ii composed of porcelain or glass in the modification shown, although other inexpensive insulating materials may be substituted therefor. The forms l0 and II have generally complementary surfaces which are corrugated as at I! and i3 in order to increase the area thereof. These surfaces are provided with spray deposited layers indicated at It and i5 respectively, of aluminum or other suitable film forming metal produced as described in my aforesaid patent and, because of their porous structure, having great capacity per unitof plane area as compared to an ordinary foil electrode. One of these surfaces, the surface it, for example, forms part of the anode, while the other surface forms part of the cathode or other electrode of the condenser.

In order further to increase the capacity of the condenser without materially enlarging its size or increasing its weight spacer members It and additional electrode elements I1 and II are positioned between the members l0 and H. The

electrode elements i1 and i8 preferablyconsist 1 of a flexible, porous material such as cloth, sprayed with molten film forming metal in the manner disclosed and claimed in my copending application Serial No. 158,105 filed August 9, 1937, these elements being flexible, porous and conductive throughout. The spacers may be of any conventional construction such as the ordinary flexible gauze spacers utilized in conventional electrolytic condensers. Because of their flexibility, the spacers and electrode elements, when assembled with members l0 and ii, conform to the contour thereof as shown particularly in Fig. 3 of the drawings. The arrangement is such that the member I! is of the same polarity as the sprayed surface i4, while the member Ill is of the same polarity as the sprayed surface l5. This produces a construction in which condenser plates of opposite polarity are inter-leaved and sprayed by insulating spacers.

The terminal connections may be made by extending the sprayed surface H to the region 20 adjacent the screws 2i and similarly extending the sprayed surface i5 to the region 22 adjacent the screws 23. These screws function to clamp the members iii and II together and to retain the whole assembly in position. At the left end of the assembly, adjacent the screw II the sprayed surface I5 is stopped short and the electrode element i8 is also stopped short adjacent the shoulder 24, while the electrode element I1 is continued beyond the screw as shown. By this construction connection to the sprayed surface i5 and the element I! may be made either through the screw 2| or through an additional terminal tab 25 which is clamped into engagement with the adjacent sprayed surfaces by the screw 2|. The spacers are continued sufficiently beyond the end sprayed surface l5 and electrode element 18 to prevent short circuiting.

At the other end of the condenser adjacent the screw '23 a similar construction is employed. That is, the sprayed surface i5 is continued beyond the screw and the electrode element [8 is extended substantially to the edge of the assembly as shown, while the element I1 is stopped short as is the spray deposited surface 14, the spacers being continued sufilciently far to prevent short 'circuiting between elements of opposite polarity.

A terminal tab 26, connected with the surface II and element l8 may be provided. As shown in the drawing, the spray deposited coatings H and I! may extend through the openings receiving the screws 2! nd 23 as indicated at 28 and 29, respectively. This is particularly desirable if the electrical connection is to be made through the screws rather than through the terminal tabs.

This type of condenser may be impregnated with a suitable paste type electrolyte such as described in my Patent No. 2,095,966 issued October 19, 1937. stices of the porous spacers and the porous spray deposited layers of aluminum or other film forming metal so that a very great capacity can be obtained in a condenser occupying a very small space. One or both of the electrodes may be provided with electrically formed dielectric films, depending upon the service for which the condenser is intended. The film may be formed in any well-known manner, preferably before assembly of the several parts, for example, by subjecting the electrode to electrolysis as an anode in an electrolyte containing a suitable film forming material such as boric acid or borax, the formation being continued until the desired low leakage is obtained at a voltage somewhat in excess of the intended service voltage of the condenser. After the formation of the dielectric film has been completed and after the condenser has been assembled and impregnated with electrolyte, it may be sealed merely by dipping the assembly in 9, suitable composition such as wax, rubber, or various synthetic resins.

In Figs. 4 and 5 I have illustrated a form of my invention adapted to condensers of th liquid type. In this modification the liquid electrolyte is retained Within a hollow tubular member 30 which is referably molded of any inexpensive insulating material which will not contaminate the electrolyte in service. Suitable materials are glass, various hard rubber compositions, or various synthetic resins such as urea formaldehyde or phenol formaldehyde resins. Any inexpensive, moldable insulating materials may be employed so long as they are inert to the action of the elec- The electrolyte permeates the inter-.

trolyte. In this connection, it is to be noted that when hard rubber is employed it should have a low sulphur content. In this form of my invention the interior surface of the member 30 is corrugated or fluted as indicated at 3i and the effective electrode area. is greatly increased by an insert 32 of flexible porous material such as cloth, and having curved portions 33 conforming to the surface of the member 30 and inwardly extending fins 34. This insert is placed within the container 30 and then the assembly sprayed with finely divided molten aluminum or other film forming metal to form the anode surfaces indicated diagrammatically at 35, the sprayed aluminum also functioning to hold the flexible form in place within the container and to stiffen it somewhat so that it will retain its shape in use.

The container may be of any convenient construction, for example, the open upper end 36 may be closed by a thin metallic cap 31 spun downwardly as at 38 around the bead 39 and provided with a suitable vent 40. The terminal for the sprayed anode surface 35 may consist of a wire ll molded into the neck portion 42 of the container 30 and extending into contact with the sprayed surface. rod 43 provided with an enlarged portion 44, and also molded into the neck portion 42. The enlarged portion serves to prevent the cathode from being displaced with relation to the neck and also assists in preventing leakage of the electrolyte around the cathode. The sprayed surfaces preferably terminate below the normal liquid level of the electrolyte 45 and the central portion 46 of the. lower surface of the container is not sprayed so that there will be no possibility of a short circuit taking place between the cathode and anode at this point.

This form of my invention may be used with any type of liquid electrolyte such as an aqueous solution of borax and boric acid, and may be provided with a dielectric film by any convenient method such as that briefly described above.

It is to be noted that the container 30, and also the members l0 and II of the previous modification, may be made of an inexpensive metal such as steel, for example, with the inner surfaces thereof protected from the electrolyte by an adherent layer of an inert insulating material such as porcelain enamel. This general type of construction is more fully described in my parent application aforesaid.

From the foregoing it will be evident that by my invention'IJhave provided electrolytic devices which can be readily and economically manufactured and which are composed principally of very inexpensive materials, the amount of metal employed being kept at a minimum. By reason of the use ot'rnaterial such as porcelain, glass, and various synthetic resins in my condensers, the danger of contamination in the condenser is reduced to a minimum and a durable, long-lived condenser is insured. The construction of my devices embodying spray deposited layers on bases of insulating material in conjunction with spray deposited layers of flexible material such as fabric produces compact condensers of high capacity and efficiency, while the use of insulating materials as bases for the sprayed layers materially reduces the amounts of high purity metals required.

In the foregoing specification I have described my invention as applied to two types of electrolytic condensers. It will be obvious that my invention may be adapted to other electrolytic devices and that various changes and modifications The cathode may comprise a may be made therein without departing from the teachings of my invention. Therefore it is to be understood that my patent is not limited to the preferred forms described herein or in any manner other than by the scope of the appended claims.

Reference is hereby made to my divisional application for Electrolytic device, executed by me on September 26, 1947, and filed in the United States Patent Oflice on or about October 2, 1947, and containing claims directed particularly to the form of the invention shown in Figures 4 and 5 hereof.

I claim:

1. An electrolytic condenser comprising two rigid members composed of insulating material, said members having corrugated complementary spaced surfaces, said surfaces being provided with spray-deposited conductive layers of finely divided particles of film forming metal, at least two fabric members having spray-deposited conductive metallic layers thereon disposed between said surfaces, one oi said fabric members being in circult with the conductive layer on one of said surfaces, the other of said fabric members being in circuit with the conductive layer on the other of said surfaces, a spacer separating said fabric members from each other, and an electrolyte permeating said fabric members and said spacer and retained by said members.

2. An electrolytic device comprising two rigid forms of ceramic material having opposed complementary, corrugated surfaces sprayed with finely divided metallic particles forming conductive layers, at least one of said layers being formed with a dielectric film, alternately disposed insulating spacers and flexible electrodes disposed between said opposed surfaces, and a film maintaining electrolyte disposed between said surfaces and in contact with said electrodes and said layers.

6 3. An electrolytic device comprising two rigid forms of ceramic material having opposed, complementary, corrugated surfaces sprayed with finely divided metallic particles forming conductive layers, and alternately disposed porous insulating spacers and porous flexible electrodes comprising fabric members having spray-deposited layers thereon disposed between said opposed surfaces.

JOSEPH B. BRENNAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,104,018 Brennan Jan. 4, 1938 2,120,815 Schno1l June 14, 1938 2,267,717 Brennan Dec. 30, 1941 2,047,452 Zahodiakin July 14,1936 1,717,488 Andrews June 18, 1929 990,274 Knapp et al. Apr. 25, 1911 1,509,186 Benner et al Sept. 23, 1924 2,028,564 Robinson et a1. Jan. 21, 1936 1,526,817 Wright Feb. 17, 1925 1,744,302 Engle et al. Jan. 21, 1930 2,104,019 Brennan Jan. 4, 1938 1,973,694 Briggse et al Sept. 18, 1934 1,774,455 Ruben Aug. 26, 1930 2,251,913 Brennan Aug. 12, 1941 2,280,789 Brennan Apr. 28, 1942 2,177,018 Claassen et al Oct. 24, 1939 FOREIGN PATENTS Number Country Date 472,097 Great Britain Sept. v16, 1937 211,255 Great Britain Feb. 21, 1924 

